如何在golang中执行net.DialTCP时设置超时？

Question

至于net.DialTCP好像得到的唯一途径net.TCPConn,我不知道如何设置超时,而这样做的DialTCP.https://golang.org/pkg/net/#DialTCP

func connectAddress(addr *net.TCPAddr, wg *sync.WaitGroup) error {
    start := time.Now()
    conn, err := net.DialTCP("tcp", nil, addr)
    if err != nil {
        log.Printf("Dial failed for address: %s, err: %s", addr.String(), err.Error())
        return err
    }
    elasped := time.Since(start)
    log.Printf("Connected to address: %s in %dms", addr.String(), elasped.Nanoseconds()/1000000)
    conn.Close()
    wg.Done()
    return nil
}

Answer 1

使用net.Dialer与任一超时或截止日期字段集.

d := net.Dialer{Timeout: timeout}
conn, err := d.Dial("tcp", addr)
if err != nil {
   // handle error
}

一种变体是调用Dialer.DialContext,并将截止时间或超时应用于上下文.

*net.TCPConn如果您特别需要该类型而不是以下类型,请键入assert net.Conn:

tcpConn, ok := conn.(*net.TCPConn)

Answer 2

一个可以使用net.DialTimeout：

func DialTimeout(network, address string, timeout time.Duration) (Conn, error)
    DialTimeout acts like Dial but takes a timeout.

    The timeout includes name resolution, if required. When using TCP, and the
    host in the address parameter resolves to multiple IP addresses, the timeout
    is spread over each consecutive dial, such that each is given an appropriate
    fraction of the time to connect.

    See func Dial for a description of the network and address parameters.